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.\" $Id: dwarf_formudata.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd June 21, 2010
.Dt DWARF_FORMUDATA 3
.Os
.Sh NAME
.Nm dwarf_formudata ,
.Nm dwarf_formsdata
.Nd return the value of a CONSTANT class attribute
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_formudata
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Unsigned *ret"
.Fa "Dwarf_Error *err"
.Fc
.Ft int
.Fo dwarf_formsdata
.Fa "Dwarf_Attribute attr"
.Fa "Dwarf_Signed *ret"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
These functions return the value associated with a DWARF attribute
describing a constant.
.Pp
Function
.Fn dwarf_formudata
sets the location pointed to by argument
.Ar ret
to the value of the attribute referenced by argument
.Ar attr ,
treating the value as an unsigned quantity.
Argument
.Ar attr
must have one of the following forms:
.Dv DW_FORM_data1 ,
.Dv DW_FORM_data2 ,
.Dv DW_FORM_data4 ,
.Dv DW_FORM_data8
and
.Dv DW_FORM_udata .
.Pp
Function
.Fn dwarf_formsdata
sets the location pointed to by argument
.Ar ret
to the value of the attribute referenced by argument
.Ar attr ,
appropriately sign extended.
Argument
.Ar attr
must have one of the following forms:
.Dv DW_FORM_data1 ,
.Dv DW_FORM_data2 ,
.Dv DW_FORM_data4 ,
.Dv DW_FORM_data8
and
.Dv DW_FORM_sdata .
.Pp
If argument
.Ar err
is not NULL, it will be used to return an error descriptor in case
of an error.
.Sh RETURN VALUES
These functions return
.Dv DW_DLV_OK
on success.
In case of an error, they return
.Dv DW_DLV_ERROR
and set argument
.Ar err .
.Sh ERRORS
These functions may fail with the following errors:
.Bl -tag -width ".Bq Er DW_DLE_ATTR_FORM_BAD"
.It Bq Er DW_DLE_ARGUMENT
Either of arguments
.Ar attr
or
.Ar ret
was NULL.
.It Bq Er DW_DLE_ATTR_FORM_BAD
The attribute referenced by argument
.Ar attr
was not of a permitted kind.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_attr 3 ,
.Xr dwarf_formblock 3 ,
.Xr dwarf_formflag 3 ,
.Xr dwarf_formref 3 ,
.Xr dwarf_formsig8 3 ,
.Xr dwarf_formstring 3 ,
.Xr dwarf_hasattr 3
